Field of the Invention
The present invention relates to a multimode optical fiber having a GI (Graded Index) type refractive index profile.
Related Background Art
It is known that a multimode optical fiber (hereinafter referred to as MMF) has a larger transmission loss because of its structure than a single-mode optical fiber (hereinafter referred to as SMF) for long-haul optical transmission. On the other hand, the MMF is widely used for short-haul information transmission like LAN (Local Area Network) because it is easy to establish fiber-fiber connection and it becomes feasible to readily construct a network by making use of low-demand-performance equipment.
In recent years, studies have been actively conducted on technologies to reduce the aforementioned transmission loss of the MMF and on expansion of the transmission bandwidth (widening of bandwidth) thereof as well, for the purpose of improvement in signal quality in the foregoing short-haul information transmission. Particularly, for achieving the widening of bandwidth in a wider wavelength range with needs for increase in transmission capacity, for example, each of U.S. Pat. Application Publication US2013/0114934A1 (Patent Literature 1), U.S. Pat. Application Publication US2013/0114935A1 (Patent Literature 2), U.S. Pat. No. 8,644,664 (Patent Literature 3), and Denis Molin, Frank Achten, Marianne Bigot, Adrin Amezcua-Correa, and Pierre Sillard, “WideBand OM4 Multi-Mode Fiber for Next-Generation 400 GHz Data Communications,” ECOC 2014, Cannes-France, P1.6 (Non Patent Literature 1) discloses the MMF the core of which has the GI refractive index profile conforming to the α-profile (which will be referred to hereinafter as GI-MMF).